Ignore unhandled arguments instead of stopping parsing.

pkg/args/lib/args.dart

Index: pkg/args/lib/args.dart
diff --git a/pkg/args/lib/args.dart b/pkg/args/lib/args.dart
index 0cb81961a3ec2c1743f09a9138c389eb3e3013c1..52176ba6d8b1c2682fc7de5a0663dd5db5876eb4 100644
--- a/pkg/args/lib/args.dart
+++ b/pkg/args/lib/args.dart
@@ -77,18 +77,17 @@
  *
  *     var parser = new ArgParser();
  *     parser.addOption('mode');
- *     parser.addFlag('verbose', defaultsTo: true);
- *     var results = parser.parse('['--mode', 'debug', 'something', 'else']);
+ *     parser.addFlag('verbose', abbr: 'v');
+ *     var results = parser.parse('['--mode', 'debug', 'skip', '-v', 'me']);
  *
  *     print(results['mode']); // debug
  *     print(results['verbose']); // true
  *
- * The [parse()] method will stop as soon as it reaches `--` or anything that
- * it doesn't recognize as an option, flag, or option value. If there are still
- * arguments left, they will be provided to you in
+ * The [parse()] method will ignore any arguments it doesn't recognize and stop
+ * if it reaches `--`. Any unhandled arguments will be provided to you in
  * [ArgResults.rest].
  *
- *     print(results.rest); // ['something', 'else']
+ *     print(results.rest); // ['skip', 'me']
  *
  * ## Specifying options ##
  *
@@ -179,7 +178,7 @@
  *
  *           [arm]       ARM Holding 32-bit chip
  *           [ia32]      Intel x86
- * 
+ *
  * To assist the formatting of the usage help, single line help text will
  * be followed by a single new line. Options with multi-line help text
  * will be followed by two new lines. This provides spatial diversity between
@@ -192,7 +191,6 @@ library args;
 
 import 'dart:math';
 
-// TODO(rnystrom): Use "package:" URL here when test.dart can handle pub.
 import 'src/utils.dart';
 
 /**
@@ -286,6 +284,7 @@ class ArgParser {
     _args = args;
     _current = 0;
     var results = {};
+    var rest = [];
 
     // Initialize flags to their defaults.
     _options.forEach((name, option) {
@@ -312,8 +311,8 @@ class ArgParser {
       if (_parseAbbreviation(results)) continue;
       if (_parseLongOption(results)) continue;
 
-      // If we got here, the argument doesn't look like an option, so stop.
-      break;
+      // If we got here, the argument doesn't look like an option, so ignore it.
+      rest.add(arg);
     }
 
     // Set unspecified multivalued arguments to their default value,
@@ -329,8 +328,9 @@ class ArgParser {
     }
 
     // Add in the leftover arguments we didn't parse.
-    return new ArgResults(results,
-        _args.getRange(_current, _args.length - _current));
+    rest.addAll(_args.getRange(_current, _args.length - _current));
+
+    return new ArgResults(results, rest);
   }
 
   /**